Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2015

Property, Plant and Equipment [Abstract]

Schedule of property, plant and equipment

For financial reporting purposes, provisions for depreciation are calculated on a straight‑line basis over the following estimated useful lives of the underlying assets:

	Years
Buildings and improvements	30-40
Machinery and equipment	5-15
Office equipment	3-10

(Dollars in thousands)	December 31, 2015			December 31, 2014
Land	$	16,726		$	14,045
Buildings and improvements	141,082			132,105
Machinery and equipment	191,459			165,979
Office equipment	42,696			36,810
	391,963			348,939
Accumulated depreciation	(237,150		)	(225,092		)
Property, plant and equipment, net	154,813			123,847
Equipment in process	23,848			26,573
Total property, plant and equipment, net	$	178,661		$	150,420